Microbiology Chapter 9

Which template DNA sequence encodes the peptide sequence phenylalanine-leucine-aspartic acid-valine?

3'-AAAAACCTACAT-5'

All new DNA strands are synthesized from

5' to 3'

If a codon of mRNA reads 5'-UUG-3', the tRNA that delivers the amino acid to this location during translation will have an anticodon of 3'-____ -5'

AAC

In DNA, the two strands of the helix are arranged in ___ orientation

Antiparallel

what is true regarding adenine and guanine?

Both are purines

DNA polymerases are responsible for

Building the DNA chain Proofreading/repair

Which component of DNA determines the 3' and 5' ends of the strands?

Carbons in the deoxyribose sugar

During which method of gene transfer are bacterial cells in direct contact?

Conjugation

Which are parts of the lactose operon?

Control locus, Structural locus, Regulator

Transcription occurs in the ____ of bacteria and the ____ of yeast cells.

Cytoplasm, nucleus

Which is true regarding DNA replication?

Each new DNA helix contains one parent strand and one newly synthesized strand

What is the name of the specialized plasmid that directs conjugation in gram-negative cells?

F factor

Cytosine pairs with

Guanine

Which enzyme unzips the DNA helix prior to the start of replication?

Helicase

DNA polymerase ____ is the main enzyme involved in the building of the new DNA chain, whereas DNA polymerase ____ is involved mostly with removing the primers and repairing damaged DNA.

III/I

Which type of operon is typically in the "off" position until the appropriate substrate is present?

Inducible operon

Which enzyme completes the final sealing of nicks in a newly synthesized DNA strand?

Ligase

What amino acid sequence is encoded by the DNA template sequence 3'-TACCGCGCTCTACCG-5'?

Methionine-Alanine-Arginine-Aspartic Acid-Glycine

The genome of a prokaryotic or eukaryotic cell includes DNA found in which sites?

Mitochondria, chloroplasts, plasmids, chromosomes

Which of the following are parts of a nucleotide in DNA?

Nitrogenous base, Phosphate, Deoxyribose sugar

___ mutation results in early termination of the protein

Nonsense

In a protozoal or fungal cell, chromosomes are located in the

Nucleus

In replication of DNA, the lagging strand is replicated in a discontinuous manner forming

Okazaki fragments

The specific order of amino acids bound to each other by peptide bonds represents the ___ structure of a protein

Primary

How does RNA differ from DNA in bacteria and eukaryotes?

RNA is single-stranded, uracil replaces thymine

During transcription, RNA polymerase synthesizes ______ from a(n) ______ template.

RNA; DNA

____ operons often contain genes coding for anabolic enzymes and are usually turned off by the end product of the reactions catalyzed by these enzymes.

Repressible

Which of the following are functions of RNA polymerase?

Synthesizes an RNA molecule from DNA template Unwinds the DNA so that transcription can take place

The complementary sequence to 5'-AAGTC-3' is 3'-______-5

TTCAG

If one strand of DNA reads 5'-AAGCGTTA-3', the complementary sequence would be 3'- ___ -5'

TTCGCAAT

Which of the following describes the primary structure of a protein?

The chain of amino acids bound by peptide bonds

How do an Hfr cell and an F+ cell differ?

The plasmid is integrated into the chromosome of an Hfr cell but not in an F+ cell.

In DNA, adenine pairs with what?

Thymine

During which process is mRNA converted into a protein?

Translation

During DNA replication, both the leading and lagging strands are synthesized in the 5' to 3' direction.

True

The tRNA ___ is complementary to the mRNA codon.

anticodon

Initiation of transcription involves ______.

binding of RNA polymerase to promoter region

tRNA (transfer RNA)

brings amino acids to the ribosome during the translation process

Transcription of the structural genes of the arg operon is inhibited when arginine

builds up and binds to and activates the repressor

Elongated genomes may fit inside the minuscule volumes of a cell because of the complex ___ of the DNA molecule

coiling

A bacterial cell described as ___ can accept soluble DNA from the surrounding environment.

competent

The lactose operon is composed of the regulator, the ______ locus, and the structural locus.

control

Protein synthesis takes place in (on) the _______ of eukaryotic cells.

cytoplasm

Chromosomes

discrete cellular structure composed of a neatly packaged DNA molecule.

DNA polymerase converts DNA into the various types of RNA during transcription.

false

Which type of mutation is generally most harmful to cells?

frameshift mutation

Random portions of host DNA are transferred by bacteriophage during ___ transduction.

generalized

Control mechanisms ensure that _____ are active only when their products are required.

genes

Where are the chromosomes of yeast cells located?

in the nucleus

After a eukaryotic mRNA has been transcribed, _______ are removed.

introns

Recombinant

is any organism that has acquired genes that originated in another organism.

Nucleotide

is the basic unit of DNA structure.

Transcription of the structural genes of the lac operon will be inhibited when

lactose concentration is low and glucose concentration is high.

Transcription of the structural genes of the lac operon will be greatest when

lactose is present in high concentrations but glucose is absent.

Which type of mutation results in a different amino acid being incorporated into a protein?

missense

An agent that induces changes in DNA is a(n)

mutagen

A permanent inheritable alteration in the DNA sequence of a cell is a(n)

mutation

What is the result of a point mutation that changes a template gene sequence from 3'-TACGCCATATAT-5' to 3'-TACGCCATCTAT-5'?

nonsense mutation

Gene expression in prokaryotes is regulated through _______.

operons

What is a small circular segment of DNA found in the cytoplasm of prokaryotes that is capable of independent replication and usually contains nonessential genes?

plasmid

Which enzyme synthesizes primer sequences during replication initiation?

primase

The initiation of transcription occurs when RNA polymerase recognizes and binds to a region of DNA called the ____ region.

promoter

During protein synthesis, many copies of a specific ____ can be synthesized from a single mRNA transcript.

protein

The prokaryotic ribosome is composed of ______ and protein.

rRNA

Two subunits of the ___comprise the site of protein synthesis

ribosome

Due to the separation of prophage DNA from the bacterial chromosome, a specific, adjacent part of the host genome is transferred during ___ transduction.

specialized

Codon

specific sequence of 3 mRNA nucleotides, based on a DNA triplet, that encodes a particular amino acid.

A special type of RNA called _______ remove introns from eukaryotic mRNA sequences.

splicesomes

____ mutations in DNA are caused by random mistakes in replication and not known to be influenced by any mutagenic agent.

spontaneous

the ___codon AUG of mRNA is associated with the tRNA anticodon UAC and the amino acid methionine.

start

Which are components of an operon in a sequence of DNA?

structural genes operator

The region of DNA that signals the end of an RNA transcript is the ___ sequence.

termination

___ involves the uptake of free DNA by competent bacterial cells.

transformation

The ribosome, composed of rRNA and protein, is involved in the process of

translation

"Jumping genes" are known as

transposons

The promoter of an operon is the location where RNA polymerase binds, whereas the operator acts as the on/off switch for transcription of the structural genes. True false question.

true

In protein synthesis, eukaryotic and prokaryotic cells show similarities in all of the following EXCEPT the

use of formyl-methionine as the first amino acid. number of proteins encoded on a single mRNA.

Which of the following is physical, as opposed to chemical, agents that can cause mutations?

x-rays and ultraviolet light